This invention relates to a pneumatic tire having an apex in the region of the carcass ply turnup. More specifically, the invention relates to a pneumatic tire having an apex comprised of a rubber containing the reaction product of a partially polymerized cashew nutshell oil resin and a methylene donor.
The term xe2x80x9capexxe2x80x9d as used herein refers to the area of the tire in the immediate proximity of the carcass ply turnup. The apex includes a rubber wedge located in the lower sidewall region above the bead and is bonded to and encased by the carcass plies. The apex also includes the area located between the lower sidewall rubber and the axially outer side of the carcass ply turnup.
A tire is a composite of several components each serving a specific and unique function yet all synergistically functioning to produce the desired performance. One important component is the carcass ply. The carcass ply is a continuous layer of rubber-coated parallel cords which extends from bead to bead and functions as a reinforcing element of the tire. The plies are turned up around the bead, thereby locking the bead into the assembly or carcass. The tire is assembled in the green (uncured) state and upon completion is then vulcanized. Conventional resorcinol-methylene donor systems are used in the apex compounds. Unfortunately, resorcinol is a volatile material and is therefore desirable to remove from the workplace. Therefore, there exists a need for a resorcinol replacement without sacrificing the beneficial properties resulting from its use.